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- Title
Spectral manifestations of the splitting of the lowest triplet levels in Pd complexes of nonsymmetric porphyrins.
- Authors
Knyukshto, V. N.; Shul’ga, A. M.; Sagun, E. I.; Zen’kevich, É. I.
- Abstract
Based on the study of the phosphorescence and phosphorescence excitation spectra of Pd(II) tetramethylporphyrin (PdTMP) and Pd(II) tetramethyldiethylporphyrin (PdTMDEP) in solutions in 2-methyltetrahydrofuran and dodecane in the temperature range 77–283 K, the occurrence of the splitting of the lowest degenerate singlet ( S 1) and triplet ( T 1, T 2) levels of porphyrin molecules is established. In the absorption of molecules of the compounds studied, two components, S 1 and S 2, are revealed in the range of allowed long-wavelength Q(0,0) transitions (530–550 nm) and four components, T 1– T 4, are observed in the range of spin-forbidden intersystem crossing transitions S 0 → T n (560–670 nm), with all the triplet levels T 1- T 4 being located below the S 1 level on the energy scale. It is shown that an increase in the degree of deformation of the porphyrin macrocycle caused by steric interactions between β alkyls and hydrogen meso atoms is accompanied by an increase in the splitting in the system of singlet levels δ E( S 2– S 1) from 120 cm−1 for PdTMDEP to 215 cm−1 for PdTMP, as well as by an increase in the splitting in the system of triplet levels δ E( T 2– T 1) from 190 cm−1 for PdTMDEP to 250 cm−1 for PdTMP.
- Subjects
PHOSPHORESCENCE spectroscopy; PORPHYRINS; TETRAPYRROLES; ISOMERISM; ELECTROCHEMICAL research; ELECTRIC distortion
- Publication
Optics & Spectroscopy, 2006, Vol 101, Issue 6, p895
- ISSN
0030-400X
- Publication type
Article
- DOI
10.1134/S0030400X06120125